Tissue-level Implants Research Articles

Marginal Bone Loss Around Early-Loaded SLA and SLActive Implants: Radiological Follow-Up Evaluation Up to 6.5 Years.

The aim of this study was to compare marginal bone loss around early-loaded SLA and SLActive tissue-level implants (Straumann Dental Implants; Institut Straumann AG, Basel, Switzerland) after a mean of 81-month follow-up period. One hundred seven SLA and 68 SLActive implants were placed in 55 patients and loaded with final restoration after 8 and 3 weeks of healing time, respectively. Marginal bone loss around implants was determined radiographically at initial and after a mean observation time ranging between 20 and 81 months. The effect of location (mandible vs maxilla), smoking habit, sex, implant length and diameter, and the type of prosthesis on the marginal bone loss was evaluated. The overall cumulative survival rate was 98.2% being 99% for SLA implants and 97% for SLActive implants. After 20-month follow-up period, mean marginal bone loss values for the SLA and SLActive implants were 0.24 and 0.17 mm, respectively. After 81 months, mean marginal bone loss for the SLA and SLActive implants reached 0.71 and 0.53 mm, respectively. Marginal bone loss was affected by the length and type of implant and patients' smoking habit after a mean observation time of 20 months. However, none of the parameters had any significant effect on the marginal bone loss after a follow-up period of 81 months. With both SLA and SLActive implants, successful clinical results could be achieved up to 6.5 years of follow-up period.

Color masking measurement for ceramic coating of titanium used for dental implants

Statement of problemPoor implant placement or thin gingival tissue and progressive bone resorption may lead to the dark metal color showing through the peri-implant soft tissue. Whether the dark color can be adequately masked is unclear. PurposeThe purpose of this in vitro study was to test the color masking effect of porcelain applied on titanium used in fabricating the polished collar of tissue level implants. Material and methodsType 4 commercially pure titanium disks and 5 porcelain dentin shades (A2, A3, B2, C2, and D3) were used. Ten titanium disk specimens per porcelain shade were airborne-particle abraded and ultrasonically cleaned. Porcelain was condensed directly on the specimens, fired, and finished (1200 grit SiC paper). The color (L*a*b* values) of the polished specimens was measured with a reflective spectrophotometer. The specimens were then ground and polished in 0.1 mm increments. Color was measured and ΔE values were calculated at each increment until the thickness at which the ΔE was greater than 3.3 was identified. The data (n=10) were statistically analyzed by ANOVA and the Tukey multiple-comparison test (α=.05). ResultsFor ceramic thicknesses greater or equal to 0.5 mm for the A2, A3, B2, and C2 shades, the ΔE was less than 3.3. This value was 0.4 mm for the D3 shade. ConclusionsThe minimum ceramic thickness required to mask the underlying titanium color is 0.5 mm for all shades except D3, which only needs 0.4 mm. L* decreased with thickness increase. Redness and yellowness increased with thickness increase.

Comparative evaluation of the effectiveness of the implantation in the lateral part of the mandible between short tissue level (TE) and bone level (BL) implant systems

Short dental implants can be an alternative method of treatment to a vertical bone augmentation procedure at sites of reduced alveolar height. However, for successful treatment, an implant system that causes a minimal marginal bone loss (MBL) should be taken into consideration.The aim of the study has been to evaluate implantation effectiveness for bone level and tissue level short implants provided in lateral aspects of partially edentulous mandible and limited alveolar ridge height. The MBL and primary as well as secondary implant stability were determined in the study.Patients were randomly divided into two groups according to the method of treatment provided. Sixteen short Bone Level Implants (OsseoSpeed TX, Astra tech) and 16 short Tissue Level Implants (RN SLActive®, Straumann) were successfully placed in the edentulous part of the mandible. The determination of the marginal bone level was based on radiographic evaluation after 12 and 36 weeks. Implant stability was measured immediately after insertion and after 12 weeks.The marginal bone level of Bone Level Implants was significantly lower compared to Tissue Level Implants. Furthermore, the Bone Level Implants had greater primary and secondary stability in comparison with Tissue Level Implants (Primary: 77.8 ISQ versus 66.5 ISQ; Secondary: 78.9 ISQ versus 73.9 ISQ, respectively).Since short Bone Level Implants showed a significantly decreased MBL 12 and 36 weeks after implantation as well as better results for the primary stability compared to Tissue Level Implants, they should preferentially be used for this mentioned indication.

Micromorphological differences of the implant-abutment junction and invitro load testing for three different titanium abutments on Straumann tissue level implants.

The aim of this study was to investigate the micromorphological differences among three commercially available titanium abutments on Straumann implants. Furthermore, the possible impact of functional loading on the micromorphology and potential complications was investigated with the use of invitro testing. Three groups of Titanium abutments (A: Straumann Variobase n=5, B: EBI best Duo n=5, and C: Implant Direct n=5) were torqued on Straumann RN implants, as according to each of the manufacturer's instructions. The implant-abutment units were scanned with Micro-CT. Three units of each group were directly sliced in the microtome and photographed under different magnifications (10×-500×) through a Scanning Electron Microscope. Six units (two from each group) were restored with cement-retained crowns, subjected to 2000,000 load cycles with loads between 30 and 300N at 2Hz, examined through Micro-CT and finally sliced and photographed as described above. The micromorphology of each unit was studied, and the total length of tight contact (<3μm) was calculated between the implant, abutment and screw contact areas. Major morphological differences were identified between the three units, as well as differences in the extent of tight contact in all areas examined. Despite the morphological differences, the 2M cycles of loading via invitro test did not result in any noticeable complications although some changes in the micromorphology were observed. The examined implant-abutment units presented with major morphological differences. Two million cycles of invitro loading did not appear to affect the stability of the units despite the micromorphological changes. These results need to be interpreted however under the limitations of the small sample size and the specific set-up of the invitro testing.

An In Vitro Evaluation of the Loosening of Different Interchangeable Abutments in Internal-Connection-Type Implants.

The aim of this study was to compare the loosening of interchangeable one-piece abutments connected to internal-connection-type implants after cyclic loading. Four implant abutment groups (n = 7 in each group) with Straumann tissue-level implants were assessed: Straumann solid abutment (group S), Southern Implants solid abutment (group SI), Implant Direct straight abutment (group ID), and Blue Sky Bio regular platform abutment (group BSB). The implant was firmly held in a special jig to ensure fixation. Abutment screws were tightened to manufacturers' recommended torque with a digital torque gauge. The hemispherical loading members were fabricated for the load cell of a universal testing machine to evenly distribute the force on the specimens and to fulfill the ISO 14801:2007 standard. A cyclic loading of 25 N at 30 degrees to the implant's long axis was applied for a duty of a half million cycles. Tightening torques were measured prior to the loading. Removal torques were measured after cyclic loading. The data were analyzed with one-way analysis of variance (ANOVA), and the significance level was set at P < .05. The mean removal torques after cyclic loading were 34.0 ± 1.1 Ncm (group S), 25.0 ± 1.5 Ncm (group SI), 23.9 ± 2.1 Ncm (group ID), and 27.9 ± 1.3 Ncm (group BSB). Removal torques of each group were statistically different in the order of group S > group BSB > groups SI and ID (P < .05). The mean reduction rates were -2.9% ± 3.2% (group S), -21.9% ± 4.8% (group SI), -20.2% ± 7.2% (group ID), and -6.9% ± 4.3% (group BSB) after a half million cycles, respectively. Reduction rates of groups S and BSB were statistically lower than those of groups SI and ID (P < .01). The standard deviation of group S was lower than group BSB. The removal torque of the original Straumann abutment was significantly higher than those of the copy abutments. The reduction rate of the groups S and BSB abutments was lower than those of the other copy abutments.

COLOR MASKING MEASUREMENT FOR CERAMIC COATING OF TITANIUM USED IN DENTAL IMPLANTS

Statement of problem: The dark metal color showing through the periimplant soft tissue as a result of poor implant placement or thin gingiva and progressive bone resorption is a common problem in implant dentistry. Purpose: The purpose of this study was to test the color masking effect of porcelain applied on titanium used in fabricating the polished collar of tissue level implants to solve this problem.Material and Methods: Type 4 commercially pure titanium disks and five porcelain dentin shades (A2, A3, B2, C2, and D3) were used. Ten titanium disk specimens per porcelain shade were air abraded and ultrasonically cleaned. Porcelain was condensed directly on the specimens, then fired and finished (1200 grit SiC paper). The color (L*a*b* values) of the polished specimens were measured using reflective spectrophotometer. The specimens were then ground and polished in 0.1 mm increments. Color was measured and ΔE values were calculated at each increment until the thickness at which the color coordinates start to change. ΔE greater than 3.3 was considered as a significant color mismatch detectable by the human eye. The data (n=10) was statistically analyzed by ANOVA/Tukey test at the 95% confidence level (α = .05).Results: ΔE was less than 3.3 as long as the ceramic thickness was ≥ 0.5 mm for A2, A3, B2, and C2 shades. For D3, ΔE was less than 3.3 as long as the ceramic thickness was ≥ 0.4 mm.Conclusions: The minimum ceramic thickness required to block the underlying titanium color is 0.5 mm for all shades except D3 which only needs 0.4 mm ceramic thickness. L* decreased with thickness increase. Redness a* and yellowness b*increased with thickness increase.

Implants in free fibula flap supporting dental rehabilitation - Implant and peri-implant related outcomes of a randomized clinical trial.

The objective of this study was to assess the difference in success rates of implants when using two or four implant-supported-overdentures following segmental mandibular reconstruction with fibula free flap. This prospective, parallel designed, randomized clinical study was conducted with 1:1 ratio. At baseline, all participants already had segmental reconstruction of mandible with free fibula flap. The participants were randomized into two groups: Group-I received implant-supported-overdentures on two tissue-level implants and Group-II received implant-supported-overdentures on four tissue-level implants. Success rates of the implants were evaluated at 3 months, 6 months and 12 months following implant loading using marginal bone level changes as well as peri-implant indices (Buser etal., 1990). 52 patients were randomized into two treatment groups (26 each), out of which 18 patients (36 implants) of Group-I and 17 patients (68 implants) of Group-II were evaluated. One implant in Group-I was lost due to infective complications and one patient in the same group had superior barrel necrosis. There was a statistically significant increase at both time points (p=0.03, p=0.04 at 6 months, 12 months) in the amount of marginal bone loss in Group-I (0.4mm, 0.5mm at 6 months, 12 months) as compared to Group-II (0.1mm, 0.2mmat 6 months, 12 months). There were no clinically significant changes peri-implant parameters between both groups. Peri-implant soft tissue hyperplasia was seen in both groups, 32% of implants at 3-months, 26% at 6-months and 3% at 12-months follow-up. The results of this study show that patients with 2-implant-supported-overdentures had higher marginal bone loss as compared to patients with 4-implant-supported-overdentures. There were no clinically significant differences in peri-implant soft tissue factors in patients with 2- or 4-implant-supported-overdentures. Hyperplastic peri-implant tissues are common in the early implant-loading phase and tend to decrease over time under appropriate management.

Implant surface roughness alterations induced by different prophylactic procedures: an in vitro study.

To evaluate surface roughness alterations at the smooth neck of dental implants after the use of eight different prophylactic procedures. 50 tissue level implants (Institut Straumann AG, Basel, Switzerland) were used for the present investigation. The smooth collar of each implant was divided into two segments, each treated with one of eight cleaning procedures: use of a rubber cup (RCZ) or a brush (BZ) combined with an abrasive paste containing zirconium or a paste derived from perlite (RCP, BP); use of 2 composite resin burs reinforced by zirconium glass fibers (F1, F2); and use of an air-polishing system with glycine powder and two power settings (AP1, AP2). The qualitative alterations were recorded by means of a laser profilometer and the mean roughness (Ra ) and mean roughness profile depth (Rz ) were reported. Twenty untreated surfaces were used as controls. The implant collars treated with RCZ (Ra =0.33μm, Rz =2.43μm) or BZ (Ra =0.30μm, Rz =3.70μm) yielded the highest roughness values, followed by the surfaces treated with RCP (Ra =0.28μm, Rz =2.02μm), with BP (Ra =0.25μm, Rz =2.16μm) and by the use of F1 (Ra =0.27μm, Rz =2.22μm) and F2 (Ra =0.27μm, Rz =2.04μm). The lowest roughness values were observed in the AP1 (Ra =0.23μm, Rz =1.60μm) and AP2 (Ra =0.16μm, Rz =1.06μm) group, respectively. Implant collars treated with AP2 yielded statistically significantly lower (P=0.01) Rz values compared with untreated surfaces. All tested procedures did not increase implant surface roughness significantly. Treatment with an air-powder abrasive system at high-pressure setting resulted in a smoothening of the implant collar surface.

Histological assessment of hard and soft tissues surrounding a novel ceramic implant: a pilot study in the minipig.

The aim of this study was to investigate clinical and soft/hard tissues histomorphological outcomes of a ceramic implant comparatively to a titanium implant in a minipig model. Eighteen soft tissue level implants (9 Ceramic with ZLA(®) surface as test, and 9 titanium SLActive(®) as control, Institut Straumann, Basel, Switzerland) were randomly placed into the mandible of 6 minipigs (n=6). Two months later, animals were sacrificed and block biopsies were obtained to assess histomorphological outcomes. Unadjusted paired comparisons, of both groups were performed using the Wilcoxon signed rank test. The Dunnett-Hsu test was used to adjust for multiple comparisons. All implants showed excellent integration into bone and soft tissue. The fBIC (distance implant shoulder to most coronal implant contact) and BIC% (percentage bone-to-implant contact) were for both groups; test: 3.95mm and 85.4%; control 3.97mm and 84.3% respectively. No difference in peri-implant mucosa height was found, however, the sulcular epithelium was significantly shorter for the ZrO2 (mean: 0.76, 95%CI: 0.46-1.06) than for the Ti (mean: 1.40, 95%CI: 1.10-1.70) (p=0.0090). Within the limits of this pilot study, no difference was found between the ceramic implant with ZLA(®) surface and a titanium implant in terms of bone tissue integration. Furthermore, the epithelial attachment favoured this ceramic implant over titanium.

Complications with allogeneic, cancellous bone blocks in vertical alveolar ridge augmentation: prospective clinical case study and review of the literature

Vertical bone augmentation in dental implantology is an indication for cancellous allogeneic bone blocks (ABB). However, these materials may lead to adverse reactions, which are known well in orthopedics but rarely published. Therefore, in this study, we performed an evaluation of the use of ABB in vertical bone augmentation in clinical dental implantology. The prospective clinical study included 20 cases with vertical augmentation using ABB and subsequent or simultaneous placement of implants in the lateral maxilla and mandible. Follow-up included panoramic radiography, tissue healing, and peri-implantitis. Because of the limited number of patients, the report was planned to be descriptive only. Loss of ABB or peri-implantitis of more than 30% of the intraosseous implant length was deemed to indicate failure. The study was cancelled after six cases because of an unexpectedly high number of complications (5 of 6; 83%). The average surveillance time was 1460 days. Three types of unsatisfying outcome were observed: type I, early complete loss of the augmentation with soft tissue defects after 3 to 8 weeks (n= 2); type II, early soft tissue maceration (up to 8 weeks) without loss of coverage and complete early bone healing with later peri-implantitis and bone loss after prosthetic loading (6 months or later; n= 2); and type III, complication-free bone healing with subsequent peri-implantitis after prosthetic loading (6 months or later; n= 1). Complications were observed in vertical augmentation with ABB and implant placement. After careful consideration, literature data were found to support these results and also suggest that tissue level implants may be advantageous in vertical bone augmentation with ABB.

Prevalence of peri-implantitis in patients not participating in well-designed supportive periodontal treatments: a cross-sectional study.

This retrospective cross-sectional study aimed to evaluate the prevalence of biologic complications of implants in patients treated by fixed implant supported prosthesis without regular maintenance program. One hundred thirty-four patients with 478 implants, installed during a 10-year period (2001-2010), were recruited for clinical and radiographic follow-up examinations. The periodontal and implant health status were assessed to determine the prevalence of peri-implant diseases. The mean±SD loading time for implants was 4.43±2.25years. Fifty-five percentage of the implants were tissue-level implants. Peri-implantitis was diagnosed in 20% of patients and 8.8% of implants. Subject-based and implant-based prevalence of mucositis amounted to 48.5% and 40%, respectively. Mean crestal bone loss in tissue-level and bone-level implants were 0.28±0.53mm and 1.37±1.5mm, respectively. Smoking and lack of keratinized mucosa was associated with peri-implantitis at an odds ratio of OR=2.57 and 3.89, respectively. After a 5-year period of loading without any regular maintenance program, one out of five patients would experience peri-implantitis. Tissue-level implants had lower values of peri-implantitis prevalence and crestal bone loss.

The influence of initial mucosal thickness on crestal bone change in similar macrogeometrical implants: aprospective randomized clinical trial.

The objective of this study was to evaluate crestal bone changes around bone- and tissue-level implants related to initial mucosal thickness. Patients received at least 2 implants: one with the prosthetic abutment connection at the crestal bone level (MC) and one with the prosthetic abutment connection at 2.5mm supra crestal (LC). Flap thickness measurements were taken using a periodontal probe after raising the buccal flap. Patients were divided into 2 groups according to the mucosal thickness-Group A (thickness, ≤2mm) and Group B (thickness, >2mm). Our study included 33 patients and 78 implants. Each patient received at least 1 implant of each type: Group A (MC), 17 implants, with a mean bone change of -0.6±0.5mm; Group B (MC), 20 with a mean bone change of -0.2±0.4mm; Group A (LC), 15 with a mean bone change of -0.1±0.5mm; and Group B (LC), 22 with a mean bone change of -0.2±0.4mm. A paired-samples t-test for groups A (MC) and B (MC) yielded a statistically significant difference (P=0.003); there was no statistically significant difference for groups A (LC) and B (LC) (P=0.518). If the initial mucosal thickness surrounding bone-level implants is more than 2mm, there is significantly less crestal bone change compared with bone-level implants placed in initial mucosal thicknesses of 2mm or less. This difference is not statistically significant when tissue-level implants are used and the implant-abutment connection is 2.5mm above the crestal bone level.

Development of Implant Stability Quotient values of implants placed with simultaneous sinus floor elevation - results of a prospective study with 109 implants.

In patients with implant placement and simultaneous sinus floor elevation (SFE), healing periods of 6months have been the standard of care for more than 25years. The primary objective of this prospective case series study was to determine what percentage of implants placed with SFE reach a threshold Implant Stability Quotient (ISQ) of ≥70 after 8weeks of healing using Resonance Frequency Analysis (RFA). A total of 109 dental implants were placed in 97 patients. SFE was carried out with a lateral window approach and a mixture of autogenous bone chips and deproteinized bovine bone mineral (DBBM). Titanium screw-type, tissue-level implants with a chemically modified SLA surface were used. ISQ values were measured after implant insertion (ISQBL ) and after 8weeks of healing (ISQ8wk ). Patients showing ISQ8wk ≥70 subsequently underwent restoration. Implants with an ISQ value<70 were recalled at 2-week intervals. The ISQ at baseline had a mean value of 68.3 (SD±9.8). At 8weeks, the mean ISQ value was 73.6 (SD±6.4). This increase was statistically significant (P<0.001). An ISQ8wk value ≥70 was observed for 91 implants (83%). One implant (0.9%) with a peri-implant infection and severe bone loss at 8weeks was considered an early failure. This study showed that 83% of implants reached the threshold level of ISQ≥70 after 8weeks, allowing an early loading protocol. The early failure rate was considered low with 0.9%. The RFA technology is a suitable method to objectively monitor implant stability longitudinally.

Crestal Bone Changes Around Implants with Implant-Abutment Connections at Epicrestal Level or Above: Systematic Review and Meta-Analysis.

The aim of this systematic review and meta-analysis was to evaluate crestal bone changes around implants when placing the implant-abutment connection at the crestal bone level or above. Medline (Pubmed), EMBASE, and Cochrane Library up to January 2014 were electronically and hand searched for any publications that evaluated radiographic crestal bone changes around nonsubmerged, rough-surfaced implants placed in healed sites in humans and loaded for a minimum of 1 year. The search yielded 1,122 publications; 1,106 could not be included. After 16 full-text articles were read and subjected to inclusion and exclusion criteria, four were included. The mean difference was -0.29 mm (95% CI, -0.58 mm to -0.01 mm). Heterogeneity between studies was observed (I2 = 95%). Significantly more crestal bone change was seen in the epicrestal implant-abutment (bone level) connection group when compared to implants with the prosthetic connection above the crestal bone level (tissue level) (P < .00001). Dental implants at bone level show significantly less crestal bone change after 1 year of loading than tissue-level implants.

A Comparative Analysis on Two Types of Oral Implants, Bone-Level and Tissue-Level, with Different Cantilever Lengths of Fixed Prosthesis.

Depending on esthetic, anatomical, and functional aspects, in implant-prosthetic restoration of a completely edentulous jaw, the selection of implant type is highly important; however, bone- and tissue-level implants and their stress distribution in bone have not yet been comparatively investigated. Hence, finite element analysis was used to study the influence of cantilever length in a fixed prosthesis on stress distribution in peri-implant bone around these two types of oral implants. A 3D edentulous mandible was modeled. In simulations, a framework with four posterior cantilever lengths and two types of implants, bone-level and tissue-level, was considered. A compressive load was applied to the distal regions of the cantilevers, and the von-Mises stress of peri-implant bone was investigated. The independent t-test and the Pearson correlation coefficient analyzed the results (α = 0.05). Stresses in the cortical bone around the bone-level implants were greater than those in the tissue-level implants with the same cantilever length. In addition, by extending the cantilever length, the stress values in peri-implant bone increased. Therefore, when the cantilever was at its maximum length, the maximum stress was in cortical bone and around the bone-level distal implants. The results of the present study indicate that treatment with tissue-level implants is potentially more advantageous than with bone-level implants for implant-supported fixed prostheses.

Periimplant bacteria associated with different transmucosal designs or smoking habits.

This study is to compare periimplant microbiota associated with implant transmucosal designs or smoking habits. Submucosal samples from healthy 52 implants were collected for analysis of bacteria associated with bone-level (n = 37) or tissue-level (n = 15) implants or smoking habits, using quantitative polymerase chain reaction. Profiles of periimplant bacteria of smokers (n = 5) were investigated using PhyloChip Array version G3 and compared with nonsmokers (n = 5). The number of bone-level implants positive for at least 1 pathogen was higher than that of tissue level; however, differences in each bacterium were insignificant. The prevalence and abundance of Treponema denticola in smokers were significantly higher than that in nonsmokers (P < 0.05). Smokers and nonsmokers exhibited similar periimplant microbiota based on the PhyloChip Array, but they could be distinguished by limiting observations to only 18 operational taxonomic units. Streptococcus macedonicus within Firmicutes and Prevotella within Bacteroidetes were more abundant in smokers compared with nonsmokers. Prevalence of putative pathogens with bone-level implants was higher than tissue-level implants in nonsmokers. Firmicutes and Bacteroidetes were significantly higher in smokers. Smoking therefore strongly influenced peri-implant bacterial composition of bone-level implant.

Implant therapy in a surgical specialty clinic: an analysis of patients, indications, surgical procedures, risk factors, and early failures.

The aim of this study was to analyze the patient pool referred to a specialty clinic for implant surgery over a 3-year period. All patients receiving dental implants between 2008 and 2010 at the Department of Oral Surgery and Stomatology were included in the study. As primary outcome parameters, the patients were analyzed according to the following criteria: age, sex, systemic diseases, and indication for therapy. For the inserted implants, the type of surgical procedure, the types of implants placed, postsurgical complications, and early failures were recorded. A logistic regression analysis was performed to identify possible local and systemic risk factors for complications. As a secondary outcome, data regarding demographics and surgical procedures were compared with the findings of a historic study group (2002 to 2004). A total of 1,568 patients (792 women and 776 men; mean age, 52.6 years) received 2,279 implants. The most frequent indication was a single-tooth gap (52.8%). Augmentative procedures were performed in 60% of the cases. Tissue-level implants (72.1%) were more frequently used than bone-level implants (27.9%). Regarding dimensions of the implants, a diameter of 4.1 mm (59.7%) and a length of 10 mm (55.0%) were most often utilized. An early failure rate of 0.6% was recorded (13 implants). Patients were older and received more implants in the maxilla, and the complexity of surgical interventions had increased when compared to the patient pool of 2002 to 2004. Implant therapy performed in a surgical specialty clinic utilizing strict patient selection and evidence-based surgical protocols showed a very low early failure rate of 0.6%.

Retrospective cohort study of 4591 Straumann implants in private practice setting, with up to 10-year follow-up. Part 1: multivariate survival analysis.

The purpose of this retrospective, noninterventional, open cohort study is to report on the long-term survival of dental implants, in private practice representing the daily realities of implant treatment. The data are analyzed to discern statistical relationships between explanatory variables and implant failure. A total of 4591 Straumann implants were placed in 2060 patients between 1999 and 2012. Patients were evaluated after 2-3 months, 1, 3, 5, and 7 years and, in some cases, up to 10 years. The cumulative survival rate (CSR) was calculated according to the life table method and illustrated with Kaplan-Meier survival curves. Univariate analysis was performed to investigate the association between study variables and time to implant-failure. Variables with P -value < 0.15 were further selected for a multivariate analysis. Statistical methods which take into account the fact that some patients have more than one implant (therefore, dependency between implants within mouth) had been applied. At the implant level, the cumulative survival rates at 3, 5, and 7 years were 99.3%, 99.0%, and 98.4%, respectively, and at the patient level, they were 98.6%, 97.7%, and 95.9%, respectively. After adjustment to possible confounders, the multivariate analysis identified a relationship between the following risk indicators for implant failure: implant location, length and design, timing of implantation, bone grafting procedures and gender. Tissue-Level implants (n = 3863) had a very high survival rate of 99% at 3 years, which was maintained over the entire study period. Bone-Level implants (n = 600) were as predictable with a survival rate of 99% up to 3 years, while Tapered Effect implants (n = 128) demonstrated a lower survival rate of 95% at 5 years. Short 6-mm implants in the mandibular posterior sites had a high survival rate of 100%, while in maxillary posterior positions a survival rate of only 87% was achieved. Patient factors such as smoking, autoimmune disease, and penicillin allergy were tending to associate with higher failure rates. High long-term survival rates were observed for a large cohort of Straumann implants. Tissue- and Bone-Level implants had higher survival rates than Tapered Effect implants, and although short implants faired well in the mandibular posterior sites, they faired less well in the maxillary posterior sites. The study represents private practice insight into large-scale, long-term implant results.

Esthetic outcome and alterations of soft tissue around single implant crowns: a 2-year prospective study.

The aim of this prospective study was to assess the esthetic outcome and alterations of peri-implant soft tissue using tissue-level implants. Furthermore, the influencing factors, including grafting and gingival biotype, of esthetic outcome of peri-implant soft tissue were also evaluated. Of 38 patients with single missing anterior tooth in maxilla were treated with a Straumann (®) Standard Plus SLA implant. Bone augmentation was performed in 24 patients. Follow-up was conducted at 12 and 24 months after definitive crowns placement. Esthetic outcome using the pink esthetic score/white esthetic score (PES/WES) and clinical parameters were evaluated. The mean PES/WES value at baseline, 1-year, and 2-year examination was 13.79, 14.87, and 14.96. Significant improvement was found between baseline and 1-year examination (P < 0.01). And the improvement between 1-year and 2-year examination was not significant (P = 0.40). The mean PES changing value in patients with thick biotype was significantly higher than those with thin biotype at 2-year after definitive crowns placement (P = 0.03). Graft procedure had an unfavorable effect on mean PES value both at baseline and at follow-up (P < 0.01). No implants were lost at 2-year examination. Three patients experienced peri-implant infection. No significant difference was found with the passage of time in modified plaque index (mPI), probing pocket depth (PPD), and modified bleeding index (mBI). According to the present prospective clinical study, it can be concluded that it is feasible to use tissue-level implant to support single crowns in esthetic area. Favorable short-term esthetic outcome and stability of soft tissue around single implant crowns can be expected in patients with or without graft. However, graft procedures might have an unfavorable effect on the esthetic outcome. Gingival biotype can be considered as prognostic factor for esthetic outcome. RCTs with long-term follow-up are needed to provide evidence for the long-term stability of peri-implant soft tissue using tissue-level implant systems.

Effects of Currently Available Surgical and Restorative Interventions on Reducing Midfacial Mucosal Recession of Immediately Placed Single‐Tooth Implants: A Systematic Review

Procedures to improve peri-implant soft-tissue outcomes of single, immediately placed implants are a topic of interest. This systematic review investigates the effect of various surgical and restorative interventions on implant mid-buccal mucosal level. An electronic search of five databases (January 1990 to December 2012) and a manual search of peer-reviewed journals for relevant articles were performed. Randomized controlled clinical trials (RCTs), prospective cohort studies, and case series with at least nine participants were included, with data on midfacial mucosal recession (MR) of immediately placed implants following various surgical and restorative interventions with a follow-up period of at least 6 months. Thirty-six studies, eight RCTs, one cohort study, and 27 case series were eligible. Six interventions were identified and reviewed: 1) palatal/lingual implant position; 2) platform-switched abutments; 3) flapless approach; 4) bone grafts to fill the gap between buccal plate and fixture; 5) connective tissue grafts; and 6) immediate provisionalization. Three studies consistently showed that palatally/lingually positioned implants had significantly less MR when using tissue-level implants. Mixed results were reported for interventions 2, 3, 5, and 6. One study was available for intervention 4 and did not show a benefit. Some interventions might be adopted to reduce the amount of MR on implants with the immediate placement approach, as suggested by the included studies, with various levels of evidence. The conflicting results among studies might be a result of differences in patient and site characteristics, e.g., tissue biotype and buccal plate thickness. Therefore, the use of these interventions might be reserved for patients with moderate to high risk of esthetic complications.